The Rock Cycle

Quartz

Hi! My name is Quin and I belong to the Quartz family. I am a mineral, which means that I am a naturally occurring, inorganic material. I live on Mauna Kea Beach, Hawaii. Right now I'm just a tiny grain of sand, but I used to be much larger.

In fact I've changed many times in the past million years, and I will change again in the future. I'm stuck in a perpetual series of changes called the Rock Cycle.

Granite

I began my life as magma, molten rock deep under the ocean in Earth's mantle. When a plume formed, I moved up through the Earth's crust. Over the next 100,000 years, I started to cool and harden. Because I cooled slowly, I was able to grow large crystals and mature into an igneous rock called Granite. Sometimes my friends called me intrusive. I was a part of the massive volcano called Kilauea.

Quartzite

Around 200,000 years ago, the activity inside the volcano was becoming more frequent and extreme. As magma began to rise, I was badly burned through the contact of intense heat. I changed into a metamorphic rock called quartzite. My body pieces were smushed together and I gained at least 500 grams over the next several years.

Obsidian

I spent the next half million years minding my own business as I cycled between molten and solid rock. Out of nowhere, Kilauea experienced a major eruption. I was pushed out of the volcano in a terrifying explosion. As soon as I reached the air, the temperature dropped at least 1,000 degrees. I felt relieved once I became lava! As I was flying through the air, I could already feel myself changing again. I was cooling so quickly that there wasn't time for crystals to form. For the first time, I felt smooth like glass. I was the extrusive igneous rock called Obsidian.

Sandstone

The next 100,000 years or so were great. I was living the good life on beautiful Wailea Beach enjoying the sunshine. I was happy, but after a while I could feel my body aging and changing once again. My smooth surface started to get rough and I suffered some concoidial fractures. I was falling apart. Before too long, I was nothing but a few small grains drifting out to sea.

At first the water was refreshing, but after I settled to the bottom of the ocean, things got worse. Other particles of silt and sand started piling up on top of me. I was becoming more dense and compact and a sticky glue was cementing me to the other particles. I had become sandstone, a sedimentary rock!

Minerals like me can be found hanging out in sandstone. We're pretty resistant to weathering and erosion, so as sandstone breaks down, we are the last ones standing. Consequently, after being uplifted for thousands of years, and catching the waves, I was back on the beach again! This time I'm quartz, which brings us back up to date. I've heard explosions in the background for months, and my sources tell me that lava is on the way. Looks like I'll soon be on another trip through the Rock Cycle.